Langmuir, Vol.10, No.7, 2064-2067, 1994
Electrochemical Detection of Anisotropic Probe Diffusion in the Liquid-Crystalline Cesium Pentadecafluorooctanoate/D2O System
Anisotropic diffusion of electroactive probes incorporated into monodomain lamellar phases of 50 wt% cesium pentadecafluorooctanoate (CsPDFO)/D2O has been detected using cyclic voltammetry. The diffusional anisotropy ratios, D(perpendicular-to)/D(parallel-to), were 2.0 for the anion [Fe(CN)6]4- and 19.3 for the positively charged (ferrocenylmethyl)trimethylammonium ion (FcMTMMA+). Differences in diffusional anisotropies for these two probes are attributed to hydrophobic and Coulombic interactions between the probe species and the ordered phase. Small time scale dependencies in the diffusion coefficients of [Fe(CN)6]4- in the lamellar phase were observed, possibly due to a perturbation of the bulk order by the electrode surface.
Keywords:ANGLE NEUTRON-SCATTERING;WATER-SYSTEM;MICELLAR SOLUTION;LAMELLAR PHASE;SELF-DIFFUSION;CONDUCTIVITY;COEFFICIENTS;SURFACTANTS